18 research outputs found
Dynamical symmetry breaking in a 2D electron gas with a spectral node
We study a disordered 2D electron gas with a spectral node in a vicinity of
the node. After identifying the fundamental dynamical symmetries of this
system, the spontaneous breaking of the latter by a Grassmann field is studied
within a nonlinear sigma model approach. This allows us to reduce the average
two-particle Green's function to a diffusion propagator with a random diffusion
coefficient. The latter has non-degenerate saddle points and is treated by the
conventional self-consistent Born approximation. This leads to a renormalized
chemical potential and a renormalized diffusion coefficient, where the DC
conductivity increases linearly with the density of quasiparticles. Applied to
the special case of Dirac fermions, our approach provides a comprehensive
description of the minimal conductivity at the Dirac node as well as for the
V-shape conductivity inside the bands.Comment: 13 pages, 4 figures, extended versio
Tool-based nanofinishing and micromachining
10.1016/j.jmatprotec.2006.03.121Journal of Materials Processing Technology1851-32-16JMPT